The differential diagnosis of congenital nystagmus.

The decision whether a nystagmus is congenital or acquired may be difficult and is of importance in patients presenting with neurological complaints. In this article, established diagnostic criteria are critically reviewed with particular emphasis on types of nystagmus waveform and their relationship to pursuit and optokinetic responses. Attention is drawn to certain acquired nystagmus which may have similar features which have hitherto been accepted as pathognomonic of congenital nystagmus. Symptoms due to congenital nystagmus are discussed and related to the oculomotor abnormalities. The importance of the characteristics of congenital nystagmus are evaluated for use in differential diagnosis.